Function watch

watch(): () => void
Starts monitoring client-side navigation and automatically calls recordView whenever the URL changes. The implementation adapts to the configured nav type:
- "hash": listens for hashchange events.
- "history": patches pushState/replaceState and listens for popstate.
- "natural": returns a no-op because full page loads already trigger views.
Returns () => void
A cleanup function that detaches any listeners and restores patched APIs.
Example
```
const stop = watch();
// ...later
stop();
```
- Defined in components/watch.ts:33